Conducting holder for luminous tube terminals



Se t. 19, 1939. 1.. F. R. BELLOWS CONDUCTING HOLDER FOR LUMINOUS TUBETERMINALS Filed March 2, 1937 2 Sheets-Sheet l max I E W6 R 4 3 Z 8 I 11J 2/ 4 p ATTORNEYS.

Sept. 19, 1939. L. F. R. BELLOWS 2,173,510

CONDUCTING HOLDER FOR LUMINOUS TUBE TERMINALS Filed March 2, 1937 2Sheets-Sheet 2 kfyi] INVENTOR.

BY 4%.MM

ATTORNEY Patented Sept. 19, 1939 UNITED STATES CONDUCTING HOLDER FORLUMINOUS TUBE TERMINALS Lewis F. R. Bellows, Detroit, Mich.

Application March 2,

2 Claims.

This invention relates to luminous tubes, and more particularly to meansfor holding or supporting such tubes through cooperation with theelectrode connections or terminals thereof in such manner as to maintainemcient and flexible electrical contact therewith.

Luminous tubes are used chiefly in electric signs or similar electricaldisplays, and a single tube may embrace several characters or units of asign or design, or it may constitute a part, or the whole, of anindividual character or unit, depending upon the size of the display. Inany event, each tube includes two or more electrode connections orso-called terminals, and in the fabrication oi the sign or other displaydevice, the terminals, disposed at right angles to the body portions ofthe tubes, are adapted to be passed through apertures in a metal backingplate and connected rearwardly thereof with electrical conductors, itbeing common in prior constructions to line the apertures through whichthe terminals are extended with relatively long bushings of porcelain orother suitable material. Tubes that are especially long are commonlysupported intermediate their ends by suitable means projecting from thefront face of the backing plate.

With respect to such prior constructions as above referred to it may bepointed out that an accumulation of moisture on the tubes and within theaforesaid bushings adjacent the terminals frequently results in acomplete grounding of the circuit or at least a leakage of current witha consequential destruction or impairment of the effectiveness of thetube.

A principal object of my invention is to eliminate the aforesaidbushings, leaving only the narrow walls that define the aperturessurrounding the tube, and to support the tubes substantially central ofthe apertures or in materially spaced relation to said narrow walls,thereby to maintain an air gap of appreciable width, desirably not lessthan one-eighth of an inch, between the tube and the surrounding metal,the area 01' said walls being so slight, due to the thinness of thebacking plate, that an accumulation or building up of moisture thereonto an extent suflicient to bridge said air gap is prevented.

Another object of my invention is to provide a yielding holder orsupport wherewith the terminal of the tube is engaged that, by reason ofits yielding character, allows for expansion, contraction and vibrationof the tube, reducing to a minimum the liability of breakage from thesecauses. Also, it permits reasonable self-adjustment of a tube to aplurality of holders, and compensates for any 1937, Serial No. 128,660

slight irregularities in the tube and its supports.

A further object of the invention is to provide a comparatively simpleyet highly effectual electrical connection between the tube terminal andconductor that affords a multiplicity of contacts 6 thereby to insureample carrying capacity at all times.

A iurther object is to provide a simple construc tion that facilitateslongitudinal adjustment of the terminal with relation to its holder orsupport. 10

In display devices of the kind wherewith the invention is concerned, itis essential that the conductors carrying the required high voltagecurrent be well supported in properly spaced relation to and effectivelyinsulated from the metal backing plate.

It is a further object of my invention, therefore, to provide aconstruction that aifords adequate insulation and firm support andaccurate positioning of the conductors.

Additional objects of a more specific nature are the production of aneflicient insulating post for supporting the high voltage conductors,the same comprising a porcelain body having not only a heavily glazedexterior surface but incorporating intermediate its ends a transverselydisposed thick stratum of glaze that acts as a barrier to preventtransmission of moisture by absorption endwise through the body in caseof penetration through 30 accidental cracks or voids in the exteriorcoating; to combine with an insulating post of glazed porcelain or thelike, a metallic mounting that constitutes the means for attaching theelectrical conductor or conductors to the post without destroying orpenetrating the glaze, the same ineluding a base that dependsexclusively on an interlocking engagement with the post for itsattachment thereto, the nature of the interlocking engagement minimizingthe liability of cracking or breaking the glazed coating; to incorporatein said mounting, clamping plates attached to the base by screws whoseends occupy, normally in spaced relation to the walls thereof, recessesin the insulating post so as to avoid strains being imposed upon thepost while positively preventing 45 dislodgment of the base therefrom;to provide electrical conductors and clamping means thereforcharacterized by cooperating parts so shaped as to positively preventturning of the conductors within said means; to form each conductor withan eye and to surround the portion defining said eye with a helicaltension spring whereby the spring is constituted an annulus within whicha tube terminal may be engaged, this construction being responsible forthe yielding support and the multiplicity of contacts for the electrodeconnections or terminals more generally referred to hereinbefcre; toform the electrode connection or the embodiment of the inventionillustrated in the accompanying drawings, whereinlike referencecharacters d e s i g n a t e corresponding parts throughout the severalviews. 1 v

In the drawings, Fig. 1 is a'fragmentary rear elevation of a luminoustube sign incorporating my improvements; Fig. 2 is a section on the line22 of Fig. 1, this and the succeeding views showing the actual sizes ofthe parts as used in practice; Fig. 3 is a plan view of the parts shownin Fig. 2, omitting the backing plate and parts therebeyond," Figs. 4and 5 are sections on the respective lines 44 and 5-5 of Fig. 2; Fig. 6is a fragmentary elevational view of the insulating post with twoconductors clamped thereto, and Fig. 7 is a plan view of the insulatingpost with the clamping plates and screws omitted and a part of the baseof the conductor clamp broken away.

In the example selected for illustrative purposes and shown in thedrawings, the display device consists of a sign in which each individualletter is formed by a single tube incorporating two electrodeconnections or terminals. The metal backing plate, designated I, isprovided with apertures 2 through which the electrode connections orterminals 3 of the luminous tubes 4 are adapted to be extended, whenapplying said tubes to the front face of.the backing plate. The portionsof the tubes constituting the letters are spaced from, and secured to,the front face of the backing plate at points intermediate their ends byposts or supports 5 to the outer ends of which the tubes are connectedby wires 6. The posts 5 may be of any approved type and suitablyfastened to the backing plate.

Secured, as by bolts 9, to the rear side of the backing plate I inconvenient relation to the apertures 2 are'insulating posts l0. As bestshown in Figs. 2 and 4, the body of each post is made up of sections Illand Ill These sections are preferably made of porcelain. As is commonlyknown, this material is absorbent and is suitable for insulators onlywhen properly glazed. In the manufacture of myimproved insulating post,a heavy coating of glazing material is applied to the entire surface ofeach section I I1 and I0, and the protruding portion ID of the sectionl0 is engaged, within the recess Ill of the section Hi -these partspreferably being other than circular in face view and complementary toeach other so as to hold the sections in a definite relation-and theassembly, desirably in an inverted position, is then fired. This fusesthe glazing material, causing that on the interengaging parts of the twosections to amalgamate, and that on the adjacent external surfaces ofsaid sections .to flow together-at the joint between the sections, thusproducing an especially thick coating at this point. Now in case theglaze of either section becomes chipped or cracked, or, in the event ofa void in the external coating of either section, any moisture admittedto the body portion of the affected section will not reach the othersection because of the stratum of glaze between the two sections.

The post In terminates at its upper end in a boss II that is rectangularin plan and has beads I2 at its ends. These beads are interrupted atabout their middle by a groove or recess I3, and are undercut at I4where their outer surfaces merge into that of the adjacent part of thepost.

Laterally engaged with a pressed fit over the boss II is the base I5 ofconductor attaching means, the same including also clamping plates orlaws IS. The ends of the base I5 are formed to embrace the beads I2, andat like distances from, and on opposite sides of, its transverse centerthe base is formed with parallel grooves II that extend the full widthof the base-and are preferably V-shaped in cross section. Similargrooves I8 are formed along the inner edges of the clamping plates IS inopposed relation to the grooves of the base. The outer edges of theclamping plates are turned downwardly and bear on the adjacent endportions of the base. Screws 20 pass freely through holes in theclamping plates and are threaded into tapped holes in the base I5 andtherebeyond enter the recesses I3 in the beads I2. While, ordinarily,the inner ends of the screws do not engage the glazed walls of therecesses, they do serve as stops for positively preventing withdrawal ofthe base I5 from the boss II in case undue pressure is. applied theretoin a lateral direction.

Adapted to be fastened to theinsulating post ID by the attaching meansjust described are conductors 25. Each consists of a piece of stiff wireor rod, desirably bronze, that is preferably square, or at least otherthan circular, in cross section. At one end the conductor is formed toprovide an eye 26, the same being shown as in the plane of one of thediagonals of the conductor. Surrounding the portion of the conductorthat constitutes the 'eye 26 is a continuous helical tension spring 21.The two convolutions between which the conductor enters the interior ofthe spring constantly and firmly bear against the opposite sides of theconductor so that good electrical contact between the spring andconductor is always maintained at these two points, regardless of anylateral movement of the spring with respect to the eye. As previouslystated, the posts I0 are mounted on the backing plate I in convenientrelation to the apertures 2. To the insulating post that occupies thelower right hand corner of the backing plate, as the parts are viewed inFig. 1, is clamped a conductor 25 with its eye 26 substantially in axialalignment withthe adjacent aperture 2. The eye is maintained inproximate parallelism with the plane of the backing plate by reason ofthe fact that the conductor is non-rotatably supported in a givenrelation to the post I! between the base I5 and the clamping plate l6 o!the conductor attaching means. With respect to the insulating-post thatis at present under consideration, a flexible conductor 30, through itsterminal 3|, isconnected by one of the screws 20 directly to the baseI5, as will clearly appear from Figs. 1, 3 and 4, the

clamping plate ii that would normally occupy this position having beendiscarded. The eye of this conductor receives one terminal of the lu-.

minous tube that constitutes the initial letter of the sign, and theremote terminal of said tube has connection with one of the terminals ofthe tube that forms the next letter of the sign through two straightconductors that are sup- 7| ported in parallel and opposed relation toeach other by a post I that is shown as located intermediate saidterminals.

The successive letters of the present sign are connected in series andit will be observed that some of the conductors 25 are bent so as toadapt them to this particular installation, and it is when a conductoris bent that the non-rotatable connection between it and the insulatingpost is of special advantage. If the cooperating parts of the conductorsand the attaching means were not other than circular in cross section,or so formed as to prevent rotation 01' the conductors, there would belikelihood of the conductors turnin within their clamps and getting outof position.

The electrode connections or terminals 3, in the form of metallic capsapplied to the ends of the tubes 4, are shown as provided with series ofcircumferential grooves 3 for the reception of the springs 21. The endof each terminal is more or less pointed or convergent to facilitate itsentering the annulus formed by the spring, and the terminal may bepushed through the spring until the latter occupies the particulargroove that serves to locate the body of the tube in the desired spacedrelation to the front face of the backing plate. This spacing variesaccording to the nature of the display, hence the adjustment aflorded bythe series of grooves.

Having thus described my invention, what I claim is:

1. In combination, a backing plate having an aperture, a luminous tubeadapted to be given any one of a number of configurations supportedadjacent but in forwardly spaced relation to the obverse side of thebacking plate, the same having a rearwardly extending terminalprojecting in suspension through the aforesaid aperture, the distance atwhich the tube is spaced from the backing plate depending upon theconfiguration of the tube, an insulating element mounted upon thereverse side of the backing plate in spaced relation to the aperture, astill elongated electrical conductor fixedly attached to the insulatingelement, and yielding self-contracting receptacle solely sustained bythe conductor in approximate alignment with said aperture, the terminalof the tube having a series of longitudinally spaced depressions with aselected one of which said receptacle cooperates.

2. In combination, a backing plate having an aperture, a luminous tubesupported forwardly of the obverse side of the backing plate and havinga rearwardly extending terminal projecting in suspension through theaforesaid aperture, an insulating element mounted upon the reverse sideof the backing plate in arbitrarily spaced relation to the aperture, anelongated electrical conductor consisting of a relatively stiff piece ofwire fixedly attached an appreciable distance from one of its ends tothe insulating element, and a yielding self-contracting receptaclesolely sustained by the aforesaid end of the conductor, the conductorbeing bendable so as to obtain approximate alignment of the receptaclewith said aperture, and the terminal of the tube having a depressed seatspaced from its end for cooperation with the receptacle.

L. F. R. BELLOWS.

